Process of removing sulfur from petroleum hydrocarbons and apparatus



June 9, 1953 c, ZOBELL 2,641,564

PROCESS OF REMOVING SULFUR FROM PETROLEUM HYDROCARBONS AND APPARATUS Filed March 51, 1948 2 Sheets-Sheet l INVENTOR. 62/: DE; 5. 2015544 lTTGENEY' June 9, 1953 c. E. ZOBELL 2,641,564 PROCESS OF REMOVING SULFUR FROM PETROLEUM HYDROCARBGNS AND APPARATUS Filed March 51, 1948 2. Sheets-Sheet 2 IN V EN TOR. 24

C4 (/05 E.- o s L L 2 BY fiomii s Patented June 9, 1953 PROCESS OF REMOVING SULF R FROM PETROLEUM HYDROCARBONS AND APPARATUS Claude E. ZoBell, La J olla, Calif., assignor'to Tex, aco DevelopmentCorpor-ation, New York, N. Yj., a corporation of Delaware I l a Application March 31, 1948, aerial No. 18,275 r 6 Claims. (01. 1951-3) This invention relates to the purificatiomhydrogenation; and'like processing of substances, including hydrocarbons and other types of compounds, by the use of microbiological catalysts, an'd'more particularly to the reduction and removal of hydrogen-reducible compounds such as sulfur-bearing complexes or complex sulfur compounds from petroleum hydrocarbons by the use of such catalysts.

"In many cases, it is desirable to purify or alter the composition of a substance such as a petroleum hydrocarbon by hydrogenation, oftentimes without subjecting the hydrocarbon to the 'relatively high temperatures normally encountered in conventional catalytic hydrogenation. Such selective purification or alteration in many cases cannot-be accomplished feasibly and practically by chemical methods, even without the tempera ture problem. For example, crude oil, in some instances, is characterized by the presence of objectionable quantities of sulfur compounds, mostly in complex forms, which it is desirable to remove or substantially reduce in'amount, dependent upon the intended use of the final'products. 'Sulfur removal eliminates possible corrosive and other objectionable characteristics of such products when put in use. Such: sulfur compounds are further 1 objectionable inv :such final products as fuelsfor'internal'combustion engines in that they reduce the efficiency of anti.-

knock compounds suchasxtetraethylilead and may, when used'alone, reduce the octanenumber'of the fuel- It is not desirable to processsuch crudes by'conventional refining means becauseof the corrosive efiect of the sulfur :compounds. Modifications of the usual refining processes plus additional steps are required in the refiningof such crudeseither to abstract the sulfur compounds, to reduce them to unobjectionable amounts or to modify them chemically to noninterfering types. $uch process modifications require" expensive and special apparatus, involve corrosion problems, and add materially to the cost of the final-products. Desulfurization by hydrogenation, as previously known to the art, requires either special catalysts,*extremely high temperaturesor pressures, Or combinationsthereof, and consequently has not found wide applica tion. The poisoning of the catalysts by the resultant hydrogen sulfide is particularly disadvantageous. Problem's'of equal extent for sulfur 'free materials and compounds are often encountered in other types of hydrogenations.

It is an object of this inventionto provide a novelprocess' for the purification,hydrogenation t V l 2 a andsimilar processing of hydrocarbons and other types of compounds wherein microorganisms, their enzymes, or other microbiological catalysts are employed.

A more specific object of the invention is the purification of petroleum hydrocarbonsby the reduction of complex sulfur compounds therein and the removal of the resultant sulfur-containing products.

- A further object of the invention is the provision of a novel process of the type herein described wherein any hydrogen sulfide produced functions in support of the catalyst. 7

Still another object of the invention is the provision of novel'apparatus for carrying out the processiof the invention.

Other objects and advantages of the invention will appear from the following description andclaims taken in connection with the attached drawings wherein:

Fig. 1 is a diagrammatic showing of apparatus for practicing the invention in a batch process.

Fig. 2 is a modification of the apparatus of Fig. 1. l

Fig. 3 is'a horizontal section taken on the line 3-3 of Fig. 2. I Fig. i is a view similar to that of Fig. '3 of a. modification.

Fig. 5 is a further modification of the apparatus of Fig. 1'. L A

FigxB'is a section taken on the line 5--5 of Fig. 4.

' Fig. 7 is a diagrammatic showing of apparatus for practicing ,the invention. in a continuous process. 5

In brief the present invention involve the reaction of selected compounds or mixtures thereof under controlled conditions by contact with hydrogen in the presence of certain microbiological catalysts. More specifically, the invention involves the removal of selected compounds, such as complex sulfur compounds,- from petroleum hydrocarbons under controlled conditions by the reaction of such compounds with hydrogen in the presence of a microbiological catalyst such as .hydrogenase,;which activates molecular hydrogen, and other enzymes or'catalystswhich activate the substrate.

It is to be understoodthat two or more enzymes oricatalystsare usually involved in such reactions,

first, the hydrogenase, which activates hydrogen,

and second," the enzyme "or catalyst which -activates the substrateior otherreactant. The same enzymecomplex may perform both functions, or

two separate entities may be required. In other words, some bacteria which produce hydrogenase also produce enzymes which activate the reducible substrate, but this is not true of all hydrogenase-producing bacteria. Many substrates will react directly with the hydrogen activated by hydrogenase in the absence of a second enzyme or catalyst. Typical of such substrates are certain olefins, diolefins, acetylenes and amines.

Nitrate is an example of such an inorganic sub.- strate. However, the majority of substrates require another enzyme or. catalyst, separate and distinct from hydrogenase to bring about the reaction with active hydrogen produced by hydrogenase, methane and the reduction of' sulfates to sulfides are in this class as is the reduction of sulfur in cyclical sulfur compounds. The sulfur in cysteine (CSH) may be reduced to hydrogen sulfide by active hydrogen in the absence of another enzyme or catalyst but cystine (C-SC) is not so reduced under ordinary conditions of temperature, pressure and pH.

Substrate may be defined as the substance or compound acted upon, i. e., the substance which accepts hydrogen and is reduced, a substance from which hydrogen may be produced by hydrogen-producing bacteria, or. a substance from which hydrogenase may be produced by hydro genase-producing bacteria.

I Generally speaking, the substance to be treate with hydrogen is contacted with hydrogen from any suitable source in the presence of microbiological catalysts capable of activating the substrate and rendering the hydrogen sufficiently active to react with and effect the reduction or hydrogenation of selected compounds of the system. One type of microorganism or the enzyme complex therefrom may perform both functions on different types, each capable of performing different functions, may be used. In some cases,

hydrogenase alone is sufiicient as previously described.

Hydrogenase, an enzyme believed to be an iron porphyrin-protein complex, is an example of a microbiological catalyst capable of activating hydrogen and can be utilized directly as an enzyme or be produced in and from the substance'being processed as by hydrogenase-producing bacteria in the presence of a suitable nutrient medium. In some cases, another enzyme or catalyst is not required. In other cases, other microorganisms must be used as substrate activators. Such an enzyme. or combinations thereof are capable of catalyzing a number of different types of reac-- tions, some of which are hereinafter discussed.

When ,materials are ,being processed wherein it is desired to react the hydrogen with elements or radicals other than oxygen, the process ispreferably carried out in the presence of an oxygenfree gas and in the absence of any oxygen-containing compounds from which the oxygen might be liberated to combine with hydrogen. Such combination of hydrogen and oxygen would represent a loss of hydrogen.

'of hydrogen, termed by some active or nascent hydrogen, which finds an acceptor in the compounds to be hydrogenated. In the removal of sulfur complexes from crude petroleum, the active hydrogen apparently combines with the sulfur The reduction of carbon dioxide to of the sulfur complexes to form mercaptans and/or hydrogen sulfide which are readily removed and collected. The reactions are believed to be generally as follows:

Any hydrogen collected with the gaseous products of the reaction may be processed by the removal of such products and recycled. While the hydrogen in some processes such as in the treatment of crude petroleum may tend to combine with and remove other elements, the loss thereby is relatively slight and the product is usually of a nature that can be collected and marketed or otherwise utilized to advantage. For instance, any carbon removed from crude petroleum by hydrogen is usually recoverable as methane which can be considered a valuable by-product.

The process can be carried out incither a batch or a continuous method as explained hereinafter and can be controlled by varying the partial pressure of the hydrogen,temperature, pH, and like factors. The partial pressure of the hydrogen is preferably maintained within a range of 25% to about 100% of the total pressure but is capable of being varied to control the rate of the reaction. The temperatures and pH of the reactants are preferably maintained under optimum conditions as regards the action of the hydrogen and the functioning of the hydrogenase-producing bacteria and hydrogen-producing bacteria if such be used. The temperature is preferably maintained between 20 and 75 0., depending upon the types of microorganisms being used, and the pH between 6.5 and 7.5. The hydrogenase produced by some varieties of Desulfovz'brio has an optimum temperature between 60 and 65 C. Others function best between 20 and 25 C. Optimum temperatures may be raised appreciably by hydrostatic pressure. The total pressure can be raised from atmospheric to high pressure in the order of 300 atmospheres. Preferably, the pressure, because of engineering and economic considerations, is kept below 10 atmospheres.

Generally, the reaction is exothermic and some cooling may be required to remove the generated heat.

When hydrogenase is used alone in the absence of any other enzyme or catalyst, a buffer in the form of a mineral salt solution having a pH in the range of 6 to 8 is used, the exact pI-I depending upon the particular hydrogenase complex.

If microorganisms be employed to generate the hydrogenase or the hydrogen or both in the actual processing, a suitable nutrient medium is employed. In some instances'where both types of bacteria may be used and the bacteria are maintained physically separated from one another, different nutrient mediums best suited to the bacteria are employed. Since such mediums are of conventional compositions and well known to the art, further explanation thereof is not required; It is believed sufficient to state that each particular organism has its own specific requirements for a nutrient'medium. This fact is well 7 lowing microorganisms may be used to eflect the reactions indicated: 4 clos tridium aceticum and Clostridium thermoaceticum.-

Butyribacterium rettgeri.

Hydrogenomonas pantotropha.- CO2+2H2- HCHO9 carbohydrates, etc.+I-Iz Certain species of Desulfovi'brio, Sporom'brio, and other sulfate reducers catalyze reduction 0 sulfates by hydrogen:

Some species also catalyze reduction of sulfites and thiosulfates to hydrogen sulfide.

Catalysts for the reduction of sulfur-containing compounds can be isolated also from marine sediments, the cultures apparently being best in an aqueous medium of the composition of sea water enriched by:

0.02% calcium lactate 0.02% ascorbic acid 0.02% ferrous ammonium phosphate j (FeNH iPO i) 0.05% sodium bicarbonate 0.5% potassium sulfate Except when oxygen is being intentionally reacted'with hydrogen, it is desired that only anaerobic species be used to avoid the presence of oxygen and consequent undesired consumption of hydrogen. I In lieu of hydrogen from usual commercial sources, hydrogen can be secured b the bacterial fermentation of organic matter such as sewage, agricultural waste products, offal, etc., or by the alpha radiation of compounds containing hydrogen.

- Deuterium or heavy hydrogen (D2) can be substituted for hydrogen in some reducing reactions, for example, Escherichia coli is capable of catalyzing the reaction of hydrogen with fumaric acid to form dideuterosuccimc acidz let I2.

-'S0me'oth er examplesof reactions are:

Thus the present method provides a relatively simple and inexpensive process for the manufacturing of special chemicals wherein deuterium is employed.

As an example of an application of the process of the invention to a batch method, attention is directed to Fig. 1 wherein a reaction chamber In in a form resembling a storage tank is shown. Chamber I0 is provided with a valvecontrolled inlet I2 for the material to be proc essed and a valve-controlled outlet I3 for the processed material. By way of illustration, it is assumed that the substance II being processed is crude petroleum hydrocarbons and it is desired to remove or reduce the complex sulfur compounds therein. It will be noted that both inlet I2 and outlet I3 are disposed somewhat above the bottom of the storage tank. A layer I4 of nutrient medium containing both hydro-1 gen-producing bacteria, a hydrogen-producing substrate, and bacteria which produce hydrogenase and other enzymes and catalysts, is maintained in the bottom of the tank, the medium With its contained bacteria being charged through a valve-controlled inlet I5 and discharged through a valve-controlled outlet I6, By reason of the difference in the specific gravities of the material being processed such as crude oil and the nutrient 'medium which is principally water, there is-n'o substantial mixing of the two liquids. Obviously this method of practicing the invention is not desirable where the material being processed and the nutrient medium are of such specific gravities that they tend to mix, unless the two can be separated later without too much trouble. Since inlet I2 and outlet I3 are disposed above the layer of medium, the material being processed can be charged anddischarged without disturbingthe layer of medium. I

In practicing the process in this apparatus, the material to be processed is charged through in.-

The nutrient medium with its bacteria content is charged through inlet I5 and maintained as the bottom layer. It functions to produce the necessary hydrogen and microbiological catalysts. Connections I5 and I6 enable the medium to be circulated or to be replaced as desired or found necessary. It is to be understood that hydrogen from some other source may be charged to chamber [0 in'which case the nutrient medium in layer I4 will contain hydrogenase and other enzymes and catalysts or bacteria which produce same. When hydrogen is charged directly as through a manifold II,'it is distributed preferably by porous diffusers I8, usually of ceramic material, to insure optimum distribution. If desirable, hydrogenase and other activating enzymes and catalysts can be charged directly in a buffered mineral salts solution.

Oil I I remains in the tank until its processing is complete whereupon it is withdrawn through outlet I 3 and a new batch of oil charged through inlet I2. Preferably a new charge of hydrogenase or hydrogenase-producing bacteria, other enzymes or catalysts, and nutrient is charged with each succeeding batch of oil.

The resultant gaseous products of reaction' are removed through an outlet I9.

Fig. 2 shows a modification wherein a tank I 0a is modified by the provision of a central parof nutrient media.

titlon 2| of. relatively impermeable material, such as thatof the tank, and of sufiicient height to rise substantially, above layers Ma and [4b In this case, layer Ha of nutrient medium is charged with only one of the bacteria such as the hydrogen-producing bacteria. and a hydrogen-producing substrate, the layer Mb being charged with. microbiological catalysts or bacteria capable of producing such catalysts. This arrangement insures against the bacteria contacting one another in a manner that might be detrimental to one or the other since it is recognized that in some mixtures of bacteria there is a tendency for only one to survive and dominate, the other species gradually disappearing. Partition 2| is arranged to extend completely across the bottom of the tank as shown in Fig. 3.. It is to be understood that. the number of partitions may be increased and placed in different positions so that a multiplicity of separate nutrient-containing cells can be formed in any desired design.

The operation of this modification is the same as. that of Fig. 1 with the added advantage that the: bacteria are. maintained separate from one another but in. contact with the substance beingprocessed. The valved connections shown permit of charging and discharging the substance. being treated andthe nutrient media, the

latter being capable of being continuously reci'rculated,.if desired.

Fi'g. 4" is a. horizontal section like Fig. 3 illustrating a modification wherein a series of offset partitions 21a are provided in the bottom of the tank 10b in amanner similar to partition2l of Figs. 2'and 3. Nutrient. medium containing hydrogenase or any types of, bacteria can be charged at I50 and discharged at Mic. The medium can be charged periodically or continuously. In the latter case, fresh medium at the interface between the mediumyand the oil is assured;

Figs. 5 and 6 illustrate another modified form of apparatus. capable of use in" the'present process, a tank 22'being provided on its bottom with a series of longitudinally extending chambers 23a. to 23d, inclusive,.the walls of such chambers being sufilciently porous to permit the passage of hydrogen and" microbiological catalysts therethrough. It is to be, understood. that chambers 23 can be formed i'n'any' desired number and in any shape, dependent upon the desireddistribution of the-reactants-and'the catalyst Preferably the hydrogen-producing bacteria is charged throughmanifold 24 tochambers 23b and 23d andremoved through-manifold 25; The catalysts or catalyst-producing bacteria are charged-through manifold 26 to chambers 23a and 230 and removed through outlet manifold 2'1. Thus the two types of organisms are maintained entirely separate from one another while their products are permitted to circulate freely through the material being processed in the tank.

The walls of chambers 23a to 23d, inclusive, are preferably formed of unglazed porcelain or sintered glass, the pores therein being of sufiicient size to retain the bacteria and a major portion of the nutrient medium while allowing the escape of hydrogen and the catalyst. While some nutrient medium and bacteria may pass through the walls of the chambers and mix with the substance being treated, no substantial harm is done since the medium is usually of a much higher specific gravity than the substance 'beprocessed and will tend to collect in the bot tom of the tank from which it'can be drained.

The substance being treated is charged through inlet 28' and removed, after processing, through outlet 29; The gaseous products are removed through an outlet 3|.

7 In all the batcl'i'metho'ds previously described, it is: desirable to" agitate the" reactants continuously as by a. propeller or other well known means'or by proper distribution of the hydrogen when the latterbecharge'd' directly as a gas.

As anillustration ofan application of the process-of this invention in a continuousmethod, attention is directed-to Fig. 7 of the drawing wherein-a contact tower 32 of relatively simple design is shown. Tower 32' is preferably of the zonalized type in that'it is divided into zones by anumber of plates 33, the several zones 34 being connected'by bubble caps 35 and overflow pipes 36 in conventional manner. Tower 32 is provided' with an inlet 31' for the material to be processed and-an outlet 38 for the processed material. The microbiological catalysts are charged through aninlet '39 and removed at 41,. the lower portion of the tower at- 42 serving as a' settling" or separatingchamber. The reactant'gas suchas hydrogen is charged through a diffusion plate 43, preferably of porous ceramic material, toinsurethe.gasbeingevenlydistributed in the form of very fine globules.- Any unused hydrogen is discharged through an outlet 44' with the gaseous products of the reaction; the" hy: drogen" being subsequently recovered and re cycled to the tower. If desired, outlets maybe provided at different levels on the tower to remove the product mate'ri'a'l' at'difif'erent' stages during its processing. 1

Assuming that ahydrocarbon such as crude petroleum containingcomplexsulfur compounds is to be'processed, the crude'is charged through inlet 31 to tower l2; and passed upwardly from zone to'zone through bubble caps 35. Hydrogen: preferably of apurity of 25%" to'about is charged through: distributor 43 and intimately mixed with the crude'in"its passagethrough the tower. v Hydrogen ofhigh'purity can be used if a little CO2 is present and'the diluting gas is rela tively I inert, such as nitrogen. The small amount of CO is desirablesince heterotropic'bacteria require a-sma-ll amount, of COafor their" growth and reproduction. After they begin'to, multiply. and respire, they produce their own CO2 by the oxidation of carbon compounds. Autotrophic bacteria obtain-their carbon for the synthesis of all substance from C02. The necessary CO2 may be provided-bycarbonates or bicarbonates in solution in accordance with well-known dissociation equilibria. The microbiological catalysts; in this case a hydrogenase-producingbacteria or hydrogenase and other activating enzymes and catalysts with their accompanying medium, are charged to the tower through inlet 39, a maximum level thereof being maintained on each plate by the several overflow pipes 36. The medium and the catalyst eventually pass into zone 42 and out of outlet 4|.

It will be noted that the catalyst, the substance being processed, and the hydrogen are brought into intimate contact with one another in the tower, the processed material eventually being discharged through outlet 38.

It is desirable, as with the other apparatus disclosed herein that, before the process is initiated the space at the top of the tower be filled with hydrogen or some relatively inert gas since gas 11 containing Oxygen in this space would tend to dis solve in the liquid and tend to react with the hydrogen in the presence of certain catalysts to form water.

While the invention has been principally discussed herein with reference to the purification of substances, it has an equally important position in the preparation of valuable products such as methane, various organic acids, etc. In practically every case of purification or hydrogenation, the gaseous by-products are of value.

It is to be noted that the process herein disclosed is relatively simple and inexpensive to operate, particularly when the hydrogen is obtained by bacterial action on a relatively cheap substrate. The process requires a minimum of attention and is of a type that its rate can be varied over a wide range. A particularly valuable advantage is achieved by reason of the fact that any hydrogen sulfide produced does not, in most cases, poison such catalysts as are herein disclosed. For instance, hydrogenase, in most reactions, functions best in the presence of hydrogen sulfide.

The term microorganism as used herein, is intended to include molds, fungi, and bacteria as well as the microbiological enzymes and other products produced thereby.

Obviously many modifications and variations of the invention as above set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. Apparatus for effecting the reaction between a liquid material and hydrogen in the presence of enzymatic catalysts comprising a reaction chamber, at least two physically-separated tanklike compartments in the bottom of said chamber arranged to contain liquid microbiological nutrient medium of greater density than the liquid to be processed, the medium in one of said compartments being charged with an enzymatic catalyst and the medium in another compartment being charged with a hydrogen-producing bacteria, at fluid connection to charge liquid to be treated to said reaction chamber in a manner to contact the medium in said compartments, and a fluid connection to remove resultant products from said reaction chamber.

2. The apparatus of claim 1 wherein fluid connections are provided to each compartment to charge the medium therein independently of the medium in another compartment.

3. Apparatus for effecting reaction between a liquid and a gas in the presence of enzymatic catalysts comprising a reaction chamber, means to charge liquid thereto, means to charge gas thereto, means to remove resultant products therefrom, and a closed chamber within said reaction chamber for containing catalyst-produc ing bacteria and a nutrient medium therefor, the walls of said chamber being sufiiciently permeable to enable the passage of the generated catalyst therethrough without permitting escape of substantial amounts of bacteria.

4. Apparatus for effecting reaction between a liquid material and microbiologically-produced hydrogen in the presence of microbiological catalysts comp-rising a reaction chamber, a fluid connection to charge said liquid material and catalyst thereto, and. a closed chamber within said reaction chamber for containing hydrogen-producing microorganisms and nutrient medium therefor, the walls of said chamber being sufiiciently permeable to enable the passage of produced hydrogen therethrough Without permitting escape of substantial amounts of bacteria.

5. A method of removing sulfur from petroleum hydrocarbons containing relatively complex sulfur compounds which comprises subjecting said hydrocarbons to contact with a substantial amount of hydrogen in the presence of hydrogenase-producing microorganisms selected from the group consisting of Desulfom'b rio desulfuriccms and Sporovibrio, effecting said contact in the presence of a nutrient medium for said microorganisms whereby sulfur is split from said complex compounds in the form of gaseous products and removing said gaseous products therefrom.

6. A method of removing sulfur from petroleum hydrocarbons containing relatively complex sulfur compounds which comprises subjecting said hydrocarbons to contact witha substantial amount of hydrogen in the presence of hydrogenase-producing microorganisms selected from the group consisting of D'esulfovibrio' desulfuricans and Sporom'brio, producing said hydrogen in situ by the reaction of Clostridz'um microorganisms on carbohydrates, said contact resulting in the splitting of sulfur from said complex compounds in the form of gaseous products and removing said gaseous products from said reaction.

CLAUDE E. ZoBELL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,753,641 Beckman Apr. 8, 1930 1,813,882 Behm July 7, 1931 2,056,668 Bavin Oct. 6, 1936 2,166,017 Nagel July 11,1939 2,218,635 Borge Oct. 22, 1944 2,413,278 ZoBell Dec. 24, 1946 2,521,761 Strawinski :Sept. 12, 1950 

1. APPARATUS FOR EFFECTING THE REACTION BETWEEN A LIQUID MATERIAL AND HYDROGEN IN THE PRESENCE OF ENZYMATIC CATALYSTS COMPRISING A REACTION CHAMBER, AT LEAST TWO PHYSICALLY-SEPARATED TANKLIKE COMPARTMENTS IN THE BOTTOM OF SAID CHAMBER ARRANGED TO CONTAIN LIQUID MICROBIOLOGICAL NUTRIENT MEDIUM OF GREATER DENSITY THAN THE LIQUID TO BE PROCESSED, THE MEDIUM IN ONE OF SAID COMPARTMENTS BEING CHARGED WITH AN ENZYMATIC CATALYST AND THE MEDIUM IN ANOTHER COMPARTMENT BEING CHARGED WITH A HYDROGEN-PRODUCING BACTERIA, A FLUID CONNECTION TO CHARGE LIQUID TO BE TREATED TO SAID REACTION CHAMBER IN A MANNER TO CONTACT THE MEDIUM IN SAID COMPARTMENTS, AND A FLUID CONNECTION TO REMOVE RESULTANT PRODUCTS FROM SAID REACTION CHAMBER.
 5. A METHOD OF REMOVING SULFUR FROM PETROLEUM HYDROCARBONS CONTAINING RELATIVELY COMPLEX SULFUR COMPOUNDS WHICH COMPRISES SUBJECTING SAID HYDROCARBONS TO CONTACT WITH A SUBSTANTIAL AMOUNT OF HYDROGEN IN THE PRESENCE OF HYDROGENASE-PRODUCING MICROORGANISMS SELECTED FROM THE GROUP CONSISTING OF DESULFOVIBRIO DESULFURICANS AND SPOROVIBRIO, EFFECTING SAID CONTACT IN THE PRESENCE OF A NUTRIENT MEDIUM FOR SAID MICROORGANISMS WHEREBY SULFUR IS SPLIT FROM SAID COMPLEX COMPOUNDS IN THE FORM OF GASEOUS PRODUCTS AND REMOVING SAID GASEOUS PRODUCTS THEREFROM. 